Tandem dyes

Preparation of a series of phycobiliprotein tandem dyes allows multiplexed analysis of different targets in a sample. In addition, since RPE can be excited by the argon-ion laser at 488 nm, a fluorescein-labeled probe can be used concurrently with RPE alone and RPE-tandem conjugates to create a multiplexed system of different fluorescent probes that can be used simultaneously. Table 9.3 shows the different combinations of dyes that can be used in this type of assay with RPE and APC. 

Photons, 60-62, 66 Phototoxic dyes, 172 Phycoerythrin (PE), 64t, 69t, 252 from algae for conjugation to antibodies, 70-71 in tandem dyes, 71 on calibration beads, 96 providing autofluorescent signatures for flow analysis of algae, 203, 204f, 205f... 

Talbot, David, 190 Tandem dyes, 71-72, 255 Tape back-up, 43 Temporal resolution, 17 Terminal deoxynucleotidyl transferase (TdT), 153... 

Durr M., Bamedi A., Yasuda A. and NeUes G. (2004), Tandem dye-sensitized solar cell for improved power conversion efficiencies , Appl. Phys. Lett. 84, 3397-3399. 

K. Ukonaho, T Loevgren, T Soukka, T. Tandem dye acceptor used to enhance upconversion fluorescence resonance energy transfer in homogeneous assays. Anal. Chem. 2007, 79, 6312-6318. 

After dyeing, the fabric is dried quickly to a moisture content below that at which migration can occur and then either steamed or baked (thermofixed), followed by a washing-off process. All the processes mn continuously and in tandem, the fabric passing from one process and machine to the next. 

LC-TSP-MS without tandem mass capabilities has only met with limited success for additive analysis in most laboratories. Thermospray ionisation was especially applied between 1987 and 1992 in combination with LC-MS for a wide variety of compound classes, e.g. dyes (Fig. 7.31). Thermospray, particle-beam and electrospray LC-MS were used for the analysis of 14 commercial azo and diazo dyes [594]. No significant problems were met in the LC-TSP-MS analysis of neutral and basic azo dyes [594,595], at variance with that of thermolabile sulfonated azo dyes [596,597], LC-TSP-MS has been used to elucidate the structure of Basic Red 14 [598]. The applications of LC-TSP-MS and LC-TSP-MS in dye analysis have been reviewed [599]. 

Ajayaghosh A, George SJ, Schenning APHJ (2005) Hydrogen-Bonded Assemblies of Dyes and Extended jr-Conjugated Systems. 258 83-118 Akai S, Kita Y (2007) Recent Advances in Pummerer Reactions. 274-. 35-76 Albert M, Fensterbank L, l.acote E, Malacria M (2006) Tandem Radical Reactions. 264 1-62 Alberto R (2005) New Organometallic Technetium Complexes for Radiopharmaceutical Imaging. 252 1-44... 

Nau WM, Ghale G, Hennig A et al (2009) Substrate-selective supramolecular tandem assays monitoring enzyme inhibition of arginase and diamine oxidase by fluorescent dye displacement from calixarene and cucurbituril macrocycles. J Am Chem Soc 131 11558-11570... 

A separation method using RP-HPLC and electrospray-tandem mass spectrometry was developed for the simultaneous determination of Sudan-azo dyes in hot chilli products. The chemical structures of the azo dyes included in the investigation are listed in... 

T. Reemtsma, Analysis of sulfophtalimide and some of its derivatives by liquid chromatogra-phy-electrospray ionization tandem mass spectrometry. J. Chromatogr., 919 (2001) 289-297. C. Rafols and D. Barcelo, Determination of mono- and disulfonated azo dyes by liquid-chro-matography-atmospheric pressure ionization mass spectrometry. J. Chromatogr.A, 111 (1997) 177-192. 

Richardson SD, Thruston AD, McGuire JM, Weber EJ (1993) Structural characterization of reactive dyes using liquid secondary ion mass spectrometry/tandem mass spectrometry. Environmental Protection Agency (EPA) Rep EPA600J93423, p 99... 

Fig. 18.1 Modus operandi of n-type (top left), p-type (top right), and tandem DSSCs (bottom). SA and SD are acceptor and donor dyes, respectively. Ef, cb, and vb are Fermi level, conduction band, and valance band, respectively, e and h+ refer to electron and hole current, respectively.

To detail DSSC technologies, Fig. 18.1 illustrates the modus operandi of DSSCs. Initially, light is absorbed by a dye, which is anchored to the surface of either n- or p-type semiconductor mesoporous electrodes. Importantly, the possibility of integrating both types of electrodes into single DSSCs has evoked the potential of developing tandem DSSCs, which feature better overall device performances compared to just n-or p-type based DSSCs [19-26]. Briefly, n-type DSSCs, such as TiOz or ZnO mesoporous films, are deposited on top of indium-tin oxide (ITO) or fluorine-doped tin oxide (FTO) substrates and constitute the photoanodes. Here, charge separation takes place at the dye/electrode interface by means of electron injection from the photoexcited dye into the conduction band (cb) of the semiconductor [27,28]. A different mechanism governs p-type DSSCs, which are mainly based on NiO electrodes on ITO and/or FTO substrates... 

Figure 28 Tandem solar cell where monodirectional antenna systems with three dyes are put between two w-type semiconductors with different hand gaps.

This cell involves the absorption of light by dye molecules spread on the surface of the semiconductor, which upon light absorption will inject electrons into the conduction band of the n-type semiconductor from their excited state. The photo-oxidized dye can be used to oxidize water and the complementary redox process can take place at the counter electrode [46,47]. Tandem cells such as these are discussed in Chapter 8. 

Reverse-phase columns with a gradient elution in combination with UV-Vis spectrophotometers using photodiode-array (PDA) (Fig. 1.6) and spectrofiuorimeters are common devices employed in this technique. In a lesser extent, MS, tandem mass spectrometry (MS-MS), and nano liquid chromatography-electrospray ionization-quadrupole time-of-flight tandem mass spectrometry (nanoLC-nanoESI-Q-qTOF-MS-MS) has been used as detection system. This instrumentation has been mainly used in the analysis of dyes and proteinaceous media, and in some extent, in the analysis of drying oils and terpenoid varnishes [47,48],... 

DSSCs are photoelectrochemical solar devices, currently subject of intense research in the framework of renewable energies as a low-cost photovoltaic device. Their functioning is based on the interlacing of subsystems working in tandem the photoanode on which the dye sensitizer is adsorbed, the electron mediator, and the counter electrode. In this chapter, we have tried to give an overview on the recent advances in the design of these solar cell components. 

Because the characterization of support-bound intermediates is difficult (see below), solid-phase reactions are most conveniently monitored by cleaving the intermediates from the support and analyzing them in solution. Depending on the loading, 5-20 mg of support will usually deliver sufficient material for analysis by HPLC, LC-MS, and NMR, and enable assessment of the outcome of a reaction. Analytical tools that are particularly well suited for the rapid analysis of small samples resulting from solid-phase synthesis include MALDI-TOF MS [3-5], ion-spray MS [6-8], and tandem MS [9]. MALDI-TOF MS can even be used to analyze the product cleaved from a single bead [5], and is therefore well suited to the identification of products synthesized by the mix-and-split method (Section 1.2). The analysis and quantification of small amounts of product can be further facilitated by using supports with two linkers, which enable either release of the desired product or release of the product covalently bound to a dye [10-13], to an isotopic label [11], or to a sensitizer for mass spectrometry [6,14,15] (e.g., product-linker-dye- analytical linker -Pol). 

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